More ACA competition comes with a catch for consumers

People in many parts of the country will have more insurance plans to choose from this time than they did during the last ACA enrollment window.

That's good, but there's a catch. People who already have ACA coverage, and who renew their policies automatically without going back through HealthCare.gov, could see their costs rise.

What they're saying: "This year people might get complacent because they hear the average premium is going down, but that still hides enormous variation," according to the Kaiser Family Foundation's Larry Levitt.

20% of current enrollees will have just 1 plan to choose from — down from 29% a year ago.

57% of current enrollees will have at least 3 plans to choose from — up from 44% a year ago.

How it works: If you're buying coverage through the exchanges and getting a subsidy to help pay your premium (as most enrollees do), the size of that subsidy is based on your income and the cost of a specific plan in your area.

As new plans come onto the market in your area, subsidies might now be tied to one of those plans — which means the value of the subsidy will change, and it may cover less of your costs for the same plan.

(If you really want to go deep on how all this works, I wrote a treatise on it in a previous life.)

The bottom line: Enrollees who don't go back through the shopping process could have to pay more.